U.S. patent application number 11/019125 was filed with the patent office on 2005-07-14 for thermal airflow tool and system.
Invention is credited to Ben-Nun, Joshua.
Application Number | 20050154384 11/019125 |
Document ID | / |
Family ID | 34742388 |
Filed Date | 2005-07-14 |
United States Patent
Application |
20050154384 |
Kind Code |
A1 |
Ben-Nun, Joshua |
July 14, 2005 |
Thermal airflow tool and system
Abstract
A combination pressurized airflow and thermal cutting tool
constructed as a dual-use thermal airflow tool for directed heating
and drying of a specific area in surgical procedures, such as, by
way of example, in eye cataract surgery where it is primarily used
for needs related to the operation of a thermal cutting tool. The
thermal airflow tool comprises a probe having an elongated, hollow
body adapted to provide electrical power to a burning ring formed
at a distal end thereof, and an air channel for conducting
pressurized airflow to the distal end of the probe, with at least
two apertures radially disposed at the distal end of the probe. The
thermal airflow tool is in physical and electrical connection with
an air pressure unit and thermal power unit, respectively, for
directing and concentrating at least one of the pressurized airflow
and heat at the distal end of the thermal airflow tool onto a
surgical area when electrical power is applied to the thermal
airflow tool.
Inventors: |
Ben-Nun, Joshua; (Moshav
Beit-Herut, IL) |
Correspondence
Address: |
Edward Langer
c/o Sheboleth, Yisraeli, Roberts, Zisman & Co.
60th Floor
350 Fifth Avenue
New York
NY
10118
US
|
Family ID: |
34742388 |
Appl. No.: |
11/019125 |
Filed: |
December 22, 2004 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60531629 |
Dec 23, 2003 |
|
|
|
Current U.S.
Class: |
606/29 |
Current CPC
Class: |
A61F 9/007 20130101;
A61B 18/082 20130101; A61B 2018/048 20130101 |
Class at
Publication: |
606/029 |
International
Class: |
A61B 018/04 |
Claims
1. A thermal airflow tool for performing a thermal surgical
procedure, said thermal airflow tool comprising: a probe
comprising: an elongated, hollow body adapted to provide electrical
power to a burning ring formed at a distal end thereof; an air
channel for conducting pressurized airflow to said distal end of
said probe; at least two apertures radially disposed at said distal
end of said probe in a non-perpendicular plane in respect to the
axis of said hollow body for release of said pressurized airflow,
said air channel and said at least two apertures being in physical
communication with one another within said hollow body of said
probe; and an input connector mounted on a proximal end of said
probe for connecting said probe with respective sources of said
electrical power and said pressurized airflow, said input connector
having at least one resistor for controlling and monitoring the
electrical power provided to said burning ring.
2. A thermal airflow system comprising: an air pressure unit for
providing pressurized airflow having substantially linear
characteristics; a thermal power unit for providing electrical
power to said system; and a thermal airflow tool in physical and
electrical connection to said air pressure unit and said thermal
power unit, respectively, for directing and concentrating at least
one of said pressurized airflow and heat at the distal end of said
thermal airflow tool onto a surgical area when said electrical
power is applied to said thermal airflow tool.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to medical devices
and systems, and more particularly to a thermal airflow tool and an
associated system for improving thermal surgical procedure.
BACKGROUND OF THE INVENTION
[0002] Thermal surgical procedure is improved and made more
efficient by concentrating heat at a position proximate to a
surgical site. In eye cataract surgery, for example, the thermal
procedure is usually complicated by the need for multiple
instruments: a cutting tool, an air pressure inlet, a water
pressure inlet, and related surgical and electrical equipment. It
would be useful to simplify such surgical procedures by providing a
combination tool that concentrates heat on the surgical site and
which is constructed so as to be convenient to handle and which can
be used for providing both regulated heating and airflow pressure
directed to a surgical site.
SUMMARY OF THE INVENTION
[0003] Accordingly, it is a principal object of the present
invention to overcome the disadvantages of the prior art and to
provide a combination pressurized airflow and thermal cutting tool
and an associated system. The airflow and thermal cutting tool,
hereinafter thermal airflow tool of the present invention, is a
dual-use tool for directed heating and drying of a specific area in
surgical procedures, such as, by way of example, in eye cataract
surgery where it is primarily used for needs related to the
operation of a thermal cutting tool.
[0004] Thus there is provided a thermal airflow tool for performing
a thermal surgical procedure, the thermal airflow tool
comprising:
[0005] a probe comprising:
[0006] an elongated, hollow body adapted to provide electrical
power to a burning ring formed at a distal end thereof;
[0007] an air channel for conducting pressurized airflow to the
distal end of the probe;
[0008] at least two apertures radially disposed at the distal end
of the probe in a non-perpendicular plane in respect to the axis of
the hollow body for release of pressurized airflow, the air channel
and the at least two apertures being in physical communication with
one another within the hollow body of the probe; and
[0009] an input connector mounted on a proximal end of the probe
for connecting the probe with respective sources of electrical
power and pressurized airflow, the input connector having at least
one resistor for controlling and monitoring the electrical power
provided to the burning ring.
[0010] There is also provided a thermal airflow system
comprising:
[0011] an air pressure unit for providing pressurized airflow
having substantially linear characteristics;
[0012] a thermal power unit for providing electrical power to the
system; and
[0013] a thermal airflow tool in physical and electrical connection
to the air pressure unit and the thermal power unit, respectively,
for directing and concentrating at least one of the pressurized
airflow and heat at the distal end of the thermal airflow tool onto
a surgical area when electrical power is applied to the thermal
airflow tool.
[0014] The thermal airflow tool, in one embodiment of the
invention, is provided with a burn-out resistor which functions as
a fuse to limit the heating time in accordance with a predetermined
temperature setting referenced to the size orifice needed in the
thermal procedure. When the temperature has been reached, the
burn-out resistor breaks the circuit and the heating element is
turned off. The thermal airflow tool in this embodiment is for
one-time use and is constructed as a disposable plug-in unit.
[0015] In another embodiment of the invention, the thermal airflow
tool is provided with a fixed resistor of about 1000 ohms enabling
repeated use of the thermal airflow tool for burning an orifice
with a pre-set diameter in eye capsulotomy surgery.
[0016] Other features and advantages of the invention will become
apparent from the following drawings and descriptions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] For a better understanding of the invention in regard to the
embodiments thereof, reference is made to the following drawings,
not shown to scale, in which like numerals and letters designate
corresponding sections or objects throughout, and in which:
[0018] FIG. 1 is a general view of the layout of the major
components comprising the system of the invention in accordance
with an embodiment thereof;
[0019] FIGS. 2A and 2B are isometric views of the probe of the
thermal airflow tool of FIG. 1 and an enlarged, detailed view of a
burning ring in accordance with the principles of the present
invention, respectively;
[0020] FIGS. 3A-D are orthographic views of the hollow tube
construction of the probe, and axial cross-sections showing the
construction of air pressure release apertures;
[0021] FIG. 4A is an isometric view of a plug-in thermal airflow
tool in accordance with an embodiment of the invention;
[0022] FIGS. 4B and 4C are isometric external views of the plug end
and a side view, respectively, of the thermal airflow tool of FIG.
4A shown with a protective housing;
[0023] FIG. 5 is a schematic electrical diagram of an embodiment of
the invention illustrating a dual-resistor electrical circuit for
the airflow tool of FIG. 4A;
[0024] FIG. 6 is a schematic electrical diagram of another
embodiment of the invention illustrating a single-resistor
electrical circuit for the airflow tool of FIG. 4A;
[0025] FIG. 7 is a general circuit diagram of the thermal airflow
tool of FIG. 4A shown connected electrically to a central
processing unit in accordance with the principles of the
invention;
[0026] FIG. 8 is a schematic block diagram of an embodiment of the
system of the invention; and
[0027] FIG. 9 is a cross-section view of a capsulotomy application
of the airflow tool of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0028] The present invention provides a system for surgical thermal
procedures, such as for capsulotomy in eye cataract surgery, and a
dual-purpose thermal airflow tool generally useful in this as well
as in other kinds of surgical procedures. The system comprises two
main parts, an air pressure unit and a thermal power unit connected
to a thermal airflow tool.
[0029] Referring now to FIG. 1, there is shown a general view of
the layout of the major components comprising the system of the
invention in accordance with an embodiment thereof. An air pressure
unit 10 provides pressurized air for the system, while a thermal
power unit 12 provides regulated heating, suitable, for example,
for safely performing capsulotomy in eye cataract surgery (see FIG.
9). An air pressure input pipe 14 passes through a hollow handle 16
and directs airflow into thermal airflow tool 18 along a tube (see
FIG. 2) passing through the central axis of both handle 16 and
thermal airflow tool 18 when joined, as by example, with matching
connectors, as is known by those skilled in the art, so as to
direct a controlled stream of this pressurized air onto the surface
of a surgical site. In the example shown in FIG. 1, the electrical
connection to thermal unit 12 is by a three-wire power cable 24
wired from thermal power unit 12 to receptacle 22 disposed in the
distal end of handle 16.
[0030] Individual foot-pedal switches (see FIG. 8) turn the power
on/off to both units 10, 12 of the system, while controls 26 and 28
on each of the respective air pressure unit 10 and thermal power
unit 12 allow a scaled adjustment and fine-tuning control of air
and heating requirements, respectively, such as burning time, while
individual bar graph displays 30, 32 provide a user with visual
representations of the respective air pressure and heating levels
being provided closest to the surgical site at the distal end of
the thermal airflow tool 18.
[0031] FIGS. 2A and 2B are isometric views of the probe of the
thermal airflow tool of FIG. 1 and an enlarged, detailed view of a
burning ring in accordance with the principles of the present
invention, respectively.
[0032] In FIG. 2A, probe 52 is shown as a hollow tube comprising
two, electrically conducting half-sections, a negative half-section
34 and a positive half-section 36 insulated from one another by
axial cuts 38 extending along most of the length from pressurized
air input tube 42 to a burning ring 40 formed on the distal end of
probe 52. Two apertures 48, 50 are disposed adjacent to burning
ring 40 on opposing sides of the longitudinal axis of probe 52 for
advantageously concentrating and directing pressurized air onto a
surgical site (see FIG. 9 for example).
[0033] Apertures 48, 50 are formed in a non-perpendicular plane in
relation to the axis of probe 52 leaving just a small amount of
material which forms neck pieces 49, 51 physically and electrically
connecting burning ring 40 with each half-section 34, 36
respectively. Burning ring 40 comprises a thin metal ring obliquely
truncated in a plane parallel to the plane of apertures 48, 50 so
as to facilitate maximal contact with the surface of a surgical
site, such as the spherical surface of an eye when the thermal
airflow tool is used in this application (FIG. 9).
[0034] Burning ring 40 is heated when an electric current is
applied to contact points in electrical contact with burning ring
40 via the two neck pieces 49, 51 which secure burning ring 40 to
each of the electrically conducting half-sections 34, 36. Burning
ring 40 is fabricated of a heat-conducting material, such as
titanium, steel, and the like, which concentrates the heat at the
extreme distal edge of probe 52.
[0035] FIGS. 3A-D are orthographic views of the hollow tube
construction of the probe, and axial cross-sections showing the
construction of air pressure release apertures. Probe 52 of the
present invention is typically a tubular body, cylindrical in
shape, although other shapes are also usable. The interior of this
body is lined with a non-conducting, insulating material forming
sleeve 44, such as vinyl plastic, or nylon. Air input tube 42 is
also made of non-conductive material, such as rubber or plastic
(vinyl) and extends slightly outwardly from proximal end of probe
52 to join with air pressure tube 14 (see FIG. 1) connected to air
pressure unit 10 (see FIG. 1). Air input tube 42 extends internally
along the length of probe 52 to the distal end adjacent to burning
ring 40.
[0036] FIG. 4A is an isometric view of a plug-in thermal airflow
tool in accordance with an embodiment of the invention. A
non-conductive sleeve 54 retains the two half-sections 34, 36 (see
FIG. 2A) at about a mid-portion of probe 52 which is embedded in a
non-conductive, three-prong connector base 60 provided with prongs
72, 74, 76 and respective electrical contacts 62, 64, 66 on an
inner face of connector base 60. A first resistor 56 and a second
resistor 58, in a preferred embodiment of the invention, are
provided mounted between contacts 62, 64, and 66 as shown in FIG.
4A. The functions and operation of the circuit is explained below
in relation to FIG. 7.
[0037] FIGS. 4B and 4C are isometric external views of the plug end
and a side view, respectively, of the thermal airflow tool of FIG.
4A shown with a protective housing. The proximal portion of probe
52 is provided with a housing unit 68 for safety of operation and
for protecting inner components (see FIG. 4A) mounted on connector
base 60. When plugged into a matching female connector (see FIG. 1)
mounted in handle 16 (see FIG. 1), the three prongs 72, 74, 76
electrically connect probe 52 to a power source (not shown) within
thermal unit 12 (FIG. 1). Note the centrally disposed orifice 70 in
the externally oriented face of input connector base 60 to which
air input tube 42 (see FIG. 2) is tightly joined when the
respective, matching connectors are fully connected.
[0038] FIG. 5 is a schematic electrical diagram of a preferred
embodiment of the invention illustrating a dual-resistor electrical
circuit for the thermal airflow tool of FIG. 4A.
[0039] The two halves 34, 36 of the body of probe 52 serve as
positive and negative terminals in relation to one another and
burning ring 40. They are wired to the contacts 62, 64, 66
electrically connected to the three prongs 72, 74, 76 mounted in
input connector base 60. A reference resistor 56 and a second,
burn-out type resistor 58 are mounted between the outer prongs
72,76 and middle prong 74. The purpose of these resistors 56 and 58
will be explained in the description of the overall electrical
operation of the system of the invention given below in reference
to FIG. 7.
[0040] Burning ring 40 can have different diameters, from 0.5 mm up
to several millimeters. If diameters are changed, the current and
time frame inputs will be directly affected and result in different
parameters for these two factors. To control the heating level of
burning ring 40 and protect it from overheating, a calibration
resistor 56 in the range of 200 ohms to 18 kilo-ohms in ten steps
is inserted between the positive connector 62 and connector 64. A
second fuse-type resistor 58 is inserted between connector 64 and
connector 66. The values of the burn-out resistor 58 are calibrated
in accordance with the size of the diameter of burning ring 40 so
as to disable the heating portion of the thermal airflow tool 18
when current flows through the circuit, burning out the second
fuse-type resistor 58 once a pre-set temperature is reached. The
thermal operation of the airflow tool 18 is thus limited to a
single limited-life heating cycle when provided with the fuse-type
resistor 58. The thermal airflow tool is conveniently designed to
be replaceable for subsequent use by use of a quick release input
connector configured with three prongs 72, 74, 76. A matching
female connector 22 on the handle 16 (see FIG. 1) provides for
quick-release and replacement of the thermal airflow tool.
[0041] When a current is applied through electrical power connector
66 and power connector 62 to two points in an angle of 180.degree.
of the circumference, burning ring 40 heats up. The duration and
power depends on the material used, preferably a titanium alloy,
but other alloys are also usable. Titanium is used in a preferred
embodiment of the invention due to its advantageous properties of
high heat and current resistance.
[0042] FIG. 6 is a schematic electrical diagram of another
embodiment of the invention illustrating a single-resistor
electrical circuit for the thermal airflow tool of FIG. 4A. The
effect of using only one resistor 58 is to provide a thermal
airflow tool which is reusable if necessary, during one continued
surgical procedure on the same patient. The burn-out effect in the
use of a dual-resistor thermal airflow tool is not applicable in
this embodiment of the invention since the thermal airflow tool
continues to function within the pre-set limits of the value of the
resistor 58.
[0043] FIG. 7 is a general circuit diagram of the thermal airflow
tool of FIG. 4B shown connected electrically to a central
processing unit in accordance with the principles of the
invention.
[0044] In an initial test cycle, when a +5 voltage is applied to
the circuit at I input, the current flows through prong 72 in the
airflow tool 18 and passes through burning ring 40. In parallel,
the current passes across a load reference resistor 56 which in a
preferred embodiment of the invention is rated at between 1K to
about 20K ohms, and which is in electrical connection with resistor
R.sub.2 rated at about 10K ohms and from there through return at
ground G. Pin P.sub.1 in microprocessor 84 is activated and reads
the voltage applied to the circuit. The fuse-like resistor 58 is
determined to be operative if the reading is +5V. However, if the
voltage is less than or equal to 4.5V, the fuse-like resistor 58 is
not operative. The microprocessor is programmed to start a timer
(not shown) for using the thermal power unit 12 for a period over
about 10 to 20 minutes. A pulse of time t.sub.1, preferably of 100
ms is applied to field effect transistor F.sub.1 through pin
P.sub.3 which promptly kills fuse-resistor 58, that is, makes it
inoperative.
[0045] A second cycle in the circuit of FIG. 7 tests the reference
resistor 56 in airflow tool 18. The input voltage at I is +5V which
passes through prong 72 of airflow tool 18 and across reference
resistor 56 of the range value 1K to 20K ohms and returns to ground
G via middle test-prong 74 and across resistor R.sub.2 of 10K ohms.
The microprocessor 84 reads the reference resistor 56 whose value
is between 1K ohm and 20K ohms in a preferred embodiment of the
invention and is set in relation to the diameter of burning head
40. For example: 1K ohm represents a diameter of 1 mm; 2K ohm
represents 1.2 mm; and so on, up to 20K ohms which represents 5 mm
diameter. Furthermore, a 1K ohm value represents a reference value
of 4.5V on pin P.sub.1 of microprocessor 84 progressively
increasing up to 20K ohms which represents a 2.3V reference value
on pin P.sub.1.
[0046] Finally, the heating cycle for burning ring 40 is activated
via microprocessor 84 which switches on field effect transistor
F.sub.2 over a time t.sub.2 set between 10 ms up to 400 ms, in a
preferred embodiment of the invention, and which is determined in
relation to the diameter of burning ring 40 (read out by the
reference resistor 56). Fine adjustment can be made with the
potentiometer switch 28 on the front panel of thermal power unit
12.
[0047] FIG. 8 is a schematic block diagram of an embodiment of the
system of the invention.
[0048] A DC-motor-controlled membrane air pump 80 produces the
desired air pressure depending on rotation speed. The rotation
speed is controlled by the microprocessor 82. On the air pump
output 84, a security valve 86 is disposed to rapidly relieve
undesirable build-up of air pressure from the system. The valve 86
exhausts the pressurized air under non-current conditions to output
88. The system pressure between the valve 86 and an air filter 90
is checked by a pressure sensor 92 in communication with
microprocessor 82. The pressurized air flows out through the air
input tube 14 which is connected from air pressure unit 10 to the
thermal airflow tool 18 (see FIG. 1). Another flow control pressure
sensor 94 is disposed between filter 90 and air input tube 14 which
monitors the return air pressure. Sensor 94 checks the return
pressure and valve 96 is responsible for the release of
overpressure through exhaust 98.
[0049] To prevent system swinging, a damping air chamber 100 is
disposed between valve 94 and valve 96. Valve 96, in a preferred
embodiment of the invention, is a high-speed pulse-width-modulated
(PWM) valve chosen for its linear characteristics. The system
pressure is pre-selected by control switch 26, which is provided as
a potentiometer in a preferred embodiment of the invention, and
monitored visually with the aid of a bar graph display 32 (see FIG.
1). A convenient footswitch 102 allows for on and off control of
the air flow while freeing the surgeon's hands for necessary
manipulation of the thermal airflow tool 18. The thermal unit 12 is
controlled for time and power by a second microprocessor 104 and
pre-selected by control switch 28 which is provided as a second
potentiometer.
[0050] While connecting thermal power unit 12 to handle 16 (see
FIG. 1), the microprocessor 104 reads out the value of resistor 56
(see FIG. 7) and selects the necessary power range and time. In
parallel to the identification resistor 56, a second resistor 58
(see FIG. 7) is provided with a 1 ohm/0.125 W resistance which is
blown out (fused) by a starting current. After the second resistor
58 is blown, the microprocessor 104 is able to read out the
identification resistor 56. For a much higher identification
resistor resistance, it can never be fused. The microprocessor 104
is programmed to allow the user to use the thermal unit 12 for a
limited time only. The timer control switch 28, on thermal unit 12
is, in a preferred embodiment of the invention, a second
potentiometer, allowing a user to set this time frame.
[0051] In an alternate embodiment of the invention, the second
resistor 58 is omitted and the airflow tool is consequently
reusable, but at a fixed heating level for a given diameter burning
ring.
[0052] The burning cycle is controlled by microprocessor 104 which
is operated by second foot switch 108. The power supply 110,
connected to a power source by cable 102, is a standard 110/230 V
input and provides a 24V/5V output. An on-off power switch 112 is
provided for the power source housed within thermal power unit
12.
[0053] FIG. 9 is a cross-section view of a capsulotomy application
of the airflow tool of the invention. The thermal airflow tool 52
is inserted through the cornea 116 of an eye 115. Burning ring 40
is carefully moved into close proximity to the anterior surface 120
of the lens 122 which is situated below the iris 118 in the lumen
of the eye 115. Pressurized airflow enters probe 52 at the proximal
end (shown by arrow) and passes through an inner air input tube 42
(dashed lines) until exiting (indicated by lateral arrows) from
distal apertures 48, 50 (see above description and FIGS. 2-3). The
pressurized airflow is advantageously dispersed around as well as
directed directly onto the surgical site behind the cornea 116 and
helps maintain the full configuration of the lumen while
simultaneously, burning ring 40 decomposes the target capsule as
required. Removal of unwanted substances resulting from the surgery
is performed using conventional surgical procedures well-known to
those skilled in the art. The use of the thermal airflow tool of
the present invention leaves only a tiny hole, perhaps less than
three millimeters in diameter, in the cornea and saves making
larger incisions in the eye which might take longer to heal and
cause complications.
[0054] Having described the invention with regard to certain
specific embodiments, it is to be understood that the description
is not meant as a limitation, since further modifications may now
suggest themselves to those skilled in the art, and it is intended
to cover such modifications as fall within the scope of the
invention.
* * * * *